The present invention relates to the fields of electromagnetics and optics and more particularly to a system in which signals in the form of light pulses are communicated across a gap from a movable member to a fixed member.
At the present time there are a number of methods in which signals may be communicated between a movable member and a fixed member. For example, the movable member may be the cupola (turret) of a military tank and the fixed member may be the hull (body) of the tank. The signals to be communicated may include digital or analog electrical signals representing, for example, information relating to the firing of guns.
One method of communicating in those types of situations is to run wires or cables from the movable member to the fixed member. Cables are generally satisfactory if one member moves only a few degrees in relationship to the other. However, in the case of a tank the cupola may rotate many degrees in either direction and may do so with sharp starts and stops. The movement of wires and cables in that type of environment may prove a problem in terms of other operations.
Alternatively, it is known that a brush-type of system may be used for such communication. In the brush type of system, similarly to a brush in an electrical motor, a brush (which may be a filament or solid metal conductor) rubs against a movable armature, for example, a conductive band. The brush type of system has problems in relationship to static noise, problems arising from wear between the brush and the armature, and problems due to dirt and other adverse environmental effects.